Skeletal Ni Catalysts Prepared from Amorphous Ni–Zr Alloys: Enhanced Catalytic Performance for Hydrogen Generation from Ammonia Borane

Abstract

Skeletal Ni catalysts were prepared from Ni-Zr alloys, which possess different chemical composition and atomic arrangements, by a combination of thermal treatment and treatment with aqueous HF. Hydrogen generation from ammonia borane over the skeletal Ni catalysts proceeded efficiently, whereas the amorphous Ni-Zr alloy was inactive. Skeletal Ni prepared from amorphous Ni30 Zr70 alloy had a higher catalytic activity than that prepared from amorphous Ni40 Zr60 and Ni50 Zr50 alloys. The atomic arrangement of the Ni-Zr alloy also strongly affected the surface structure and catalytic activities. Thermal treatment of the amorphous Ni-Zr alloys at a temperature slightly lower than the crystallization temperature led to an increase of the number of surface-exposed Ni atoms and an enhancement of the catalytic activities for hydrogen generation from ammonia borane. The skeletal Ni catalysts also showed excellent durability and recyclability.

Dehydrogenation of Ammonia Borane by Metal Nanoparticle Catalysts

“…Although noble-metal-based catalysts show significant activities for H 2 generation by hydrolysis of AB, practical applications require the development of low-cost metal catalysts. − Nanoparticle catalysts based on first-row transition metals, such as Fe, Co, Ni, and Cu have shown high AB hydrolysis activities. ,, As in the case of noble-metal catalysts, supports are critical for the high catalytic performance of non-noble-metal catalysts. Polymers have also been used to stabilize non-noble-metal NPs.…”

Oxidation of Benzyl Alcohol over Nanoporous Au–CeO2 Catalysts Prepared from Amorphous Alloys and Effect of Alloying Au with Amorphous Alloys

“…Recently, we reported that the atomic arrangement of a precursor dramatically affects the structure and catalytic properties of the resultant nanoporous metal catalysts. We found that using an amorphous alloy as the precursor for a nanoporous metal catalyst leads to a finer structure than that formed using the corresponding crystalline alloy owing to the high corrosion resistance of the amorphous alloy. − It is expected that CeO 2 with a fine porous structure would be obtained using an amorphous alloy as a precursor as well. Aluminum (Al) has known to be an element which can form amorphous alloy with Ce, albeit within a limited range of composition (7%–10% Ce) and Al can be easily extracted from the alloy by chemical treatment in basic solutions.…”